Quantitative computed tomographic assessment of bone mineral density changes associated with administration of prednisolone or prednisolone and alendronate sodium in dogs.

OBJECTIVE

To evaluate whether a low-dosage regimen of prednisolone induces bone loss and whether administration of alendronate sodium prevents glucocorticoid-induced osteopenia in dogs by measuring trabecular bone mineral density (BMD) with quantitative CT.

ANIMALS

8 healthy Beagles.

PROCEDURES

In 4 dogs, prednisolone was administered PO at a dosage of 2 mg/kg once daily for 2 weeks, 1 mg/kg once daily for 4 weeks, and 0.5 mg/kg once daily for 3 weeks. In the other 4 dogs, alendronate sodium (2 mg/kg, PO, q 24 h) was whether administered for 9 weeks in addition to the same dosage of prednisolone used in the prednisolone-treated dogs. Before (day 0 [baseline]) and 21, 42, 63, and 150 days after the start of treatment, BMD of the lumbar vertebrae was measured by quantitative CT.

RESULTS

BMD in the prednisolone treatment group decreased to 84.7% of the baseline value on day 42, increased to 87.9% on day 63, and recovered to 91.6% on day 150. In the prednisolone-alendronate treatment group, BMD decreased to 91% of the baseline value on day 21, increased to 93.8% on day 63, and then recovered to 96.7% on day 150. Bone mineral density in the prednisolone treatment group was generally lower, albeit not significantly, than that of the prednisolone-alendronate treatment group on each examination day.

CONCLUSIONS AND CLINICAL RELEVANCE

BMD temporarily decreased after low-dosage prednisolone administration; however, it gradually improved during tapering of the prednisolone dosage. These results have suggested that a low dosage of prednisolone can be used with little concern for development of osteopenia in dogs.